Inspection class Remote Operated Vehicles (ROVs) are typically used to position a video camera underwater. The ROV usually contains electronics that are connected to a base station by a wire tether. Motor driven propellers called thrusters are used to move the ROV.
A problem with existing ROVs concerns the shaft seals inside the thrusters. In the past, inexpensive shaft seals were generally not used for thruster applications because of the pressure differential that occurs on either side of the seal. These seals may tolerate a pressure differential from the wet side to the dry side of 5 PSI. However, the pressure underwater increases approximately 1 PSI for every two feet of depth, so the low cost seal would leak at a depth of greater than 10 feet. ROVs may typically be used at depths of at least 25 feet. In order to solve this problem, more expensive seals are used which have a higher depth rating. The use of more expensive seals increases the production and maintenance costs of ROVs. Additionally, the traditional expensive seals are bulky and require ROVs using these seals to be constructed larger to accommodate the these seals, which also increases the production cost of the ROVs. The high costs associated with the manufacture and maintenance of traditionally built ROVs with expensive shaft seals reduces the ability for the consumer market to purchase ROVs.
Accordingly, there is a need to use less expensive shaft seals in such a way that the seals can be used at depths greater than 10 feet, which also reduces the costs of manufacturing and maintaining ROVs, thereby making ROVs more affordable to the consumer market.